Manchester United's best chance of silverware has slipped away. The failure of David Moyes' Reds to overturn the first-leg deficit in the Capital One Cup Semi Final was as telling as it was embarrassing.

Excitement built in advance of kick-off, with many United fans buoyed by Jason Burt of the Telegraph reporting that the signing of Juan Mata has moved closer to becoming a reality. The need to sign new players could not have been more apparent in the 120 minutes that followed.

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Adnan Januzaj, United's most potent creative force in the games against Chelsea and Swansea that preceded this encounter, looked tired from around the 60-minute mark. No wonder, given how much football the young man has played.

His inclusion in the starting line-up would not have been a formality if Moyes had a deeper talent pool to draw from. Even after Januzaj reached the point of apparent exhaustion, he still managed to contribute more than his senior colleagues, setting Javier Hernandez through on goal with a perfectly weighted pass and providing the cross that resulted in the Mexican's late equaliser.

Mata's signing would directly address the need to rest Januzaj in some key games, which will be necessary if Moyes is to keep the youngster fit and in form as United fight for a place in next season's Champions League.

However, more may well be needed from this transfer window to equip United with the tools necessary to climb their way to fourth place.

Once again, Manchester United's midfielders failed to impose themselves on a key game.

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Carrick's performance may have been an improvement on his recent outings. While the statistics do not look terrible, they only tell part of the story. Carrick made 72 passes with an 89 percent pass completion rate. (This is considerably less than the percentage he was making at peak levels last season, when he hit the 100 mark fairly regularly.)

Darren Fletcher saw slightly more of the ball managing, 75 passes with an 85 percent pass completion rate. Of those passes, WhoScored.com considers only three of Carrick's to be "key" and none of Fletcher's.

They managed five tackles between them. However, time and again, Sunderland players managed to get the ball into dangerous areas between midfield and attack, and United's under-fire defenders were forced to concede a number of dangerous set pieces.

While United managed to defend these well, with Chris Smalling being one of the few players in red to emerge from this game with much credit, the simple fact that Darren Fletcher had to play so many minutes—given his recent recovery from serious illness, let alone how relatively ineffective United's midfield was—shows just how few options Moyes has.

The signing of Mata will hopefully provide a significant lift to fans and players alike, but in order to perform at his best, he—and the rest of United's creative unit—will need a more solid, mobile platform on which to build.

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While it seems counterintuitive that a player would leave a team strolling towards the Serie A title to join a struggling Manchester United, Ben Burrows of the Mirror reports that United are making serious attempts to sign Arturo Vidal, a player whose energy, skill and bite would vastly improve United's midfield.

The need for a new left-back at United is ever more clear. With Patrice Evra only fit enough to feature from the 85th minute, Alexander Buttner was not comfortable against an in-form Adam Johnson, who found himself able to make seven key passes in the game, per WhoScored.com.

Finally, the penalty shoot out was very, very short of quality, and the feeling among fans, that this is a United squad that lacks leaders, felt justified.

Of course, the return of Wayne Rooney and Robin Van Persie may well be enough to paper over some of these cracks, but if Moyes is to address the fundamental issues, new players are a must.

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When the doom and gloom of the defeat lifts, perhaps the signing of Juan Mata will be the beginning of a significant recovery. Here's hoping.